Using a Weight Loss Pen: What to Expect and How to Track Your Progress

Wegovy contains semaglutide, a GLP-1 receptor agonist that acts on appetite-regulating pathways in the brain, contributing to a reduced sense of hunger and increased feelings of fullness. Mounjaro (tirzepatide) works similarly but also acts on GIP receptors, making it a dual-action medicine. Both are delivered as once-weekly injections via pre-filled pens and are prescribed as part of a broader programme that includes changes to diet and activity.

Progress is individual and non-linear

Many people notice changes in appetite — sometimes called a reduction in "food noise" — within the first few weeks. Weight changes, however, vary considerably between individuals and across time. It is common for progress to slow or pause at certain points, which can feel discouraging if the scale is your only measure. Tracking a fuller picture — energy levels, how clothes fit, mood, sleep quality, and measurements — gives a much more honest view of what is actually happening in your body.

Why plateaus happen

A plateau — a period where the scale stops moving despite continued effort — is a normal part of the journey for many people on a weight loss pen. It can reflect changes in metabolism, shifts in body composition, or simply normal biological variation. Rather than a sign that the medicine has stopped working, it is often a prompt to look more closely at patterns: sleep, protein intake, activity, and consistency all play a role. If you are concerned about a plateau or your progress, your prescriber or doctor is the right person to speak to.

For a broader look at the range of injectable options available, see our guide to weight loss pens and how they work, or explore how Mounjaro compares as a weight loss pen in terms of mechanism and approach.

The clearest way to understand your progress is to track it consistently — and that is where GLP Trackr is built to help. The app's weight and body tracking feature lets you log your weight, measurements, and weekly check-ins in one place, then shows your trend over time in a visual chart. A single number on a single day can be misleading; a trend over eight weeks tells a very different — and far more useful — story.

Go beyond the scale

GLP Trackr's daily check-in captures mood, energy, sleep, and food-noise alongside your weight, so you can start to see correlations you might otherwise miss. The insights and analytics tools surface patterns in your own data — for example, whether your best weight weeks tend to follow higher-protein days or better sleep. This kind of personal-data insight is something a weekly weigh-in alone can never give you.

Bring a clear picture to your appointments

The app's doctor report feature lets you arrive at your prescriber appointments with a clear summary of your journey — doses, weight trend, side effects, and more — so conversations are more productive and grounded in your actual experience rather than memory alone. Your prescriber or doctor should always guide any decisions about your dose or treatment; GLP Trackr helps you give them the clearest possible information to work with.

If you are early in your journey and want to understand how different pen options compare, our guide to newer weight loss pen options covers what is currently available. For a full overview of tracking your weight loss journey, visit our weight loss tracking hub.

GLP Trackr is free to try for seven days — download it on the App Store or Google Play, log your first check-in today, and start seeing your journey as a trend, not just a number.